Connections

aboundingdriprockUrban and Civil

Nov 29, 2013 (3 years and 11 months ago)

94 views

EC 5
-
1
-
1

Design of Timber Structures

Joints

Connections


EC 5
-
1
-
1

Design of Timber Structures

Joints


Joints

Overview over joints in timber constructions




Carpentry joints




Metal fasteners

a

b/u
1
1
a

b/u
a

b/u
a

u
2
a

u
2

a

,D
h
h,ef
||
0,9
4
h
n
n min
vorh.a
n
10 d








EC 5
-
1
-
1

Design of Timber Structures

Joints



End grain skew notch:

Tenon:

Low load
-
carrying capacites,
Manufacturing expensive,
expect CAM is used.

EC 5
-
1
-
1

Design of Timber Structures

Joints


Mortise and tenon joint:

EC 5
-
1
-
1

Design of Timber Structures

Joints


Metal fasteners:

Dowels Bolts


30°
30°
d
f
f
l
Kopf
Unterlegscheibe
Mutter
d
n
l
n
Glattschaftiger Nagel
nach DIN EN 10230-1
(runder Flachkopf)
Rillennagel
(Anker-/Kammnagel)
Schraubnagel
(Sparrennagel)
l
n
d
n
l
g
D
d
n
D
l
n
l
g
Nails



EC 5
-
1
-
1

Design of Timber Structures

Joints

Dowels


Fit
-
Bolts






Rope effect





Higher Load
-
carrying capacity

EC 5
-
1
-
1

Design of Timber Structures

Joints

Design of Timber Structures

EC 5
-
1
-
1

Connections

Start values

-


Embedment strength of material


(function of density)

-


Diameter of connector

d

-


Thickness of timber / wood based panel

t
1

t
2

-


Penetration length of fastener

l

-


Yield moment of fastener

Design of Timber Structures

EC 5
-
1
-
1

Connections

Start values

General:

-
Embedment strength related to density


better exploitation of material

-
For fasteners with


> 8mm

the relationship between load bearing
capacity and angle between force and grain direction has to be taken
into account (not valid for

nails with




8mm)

-
For screws with


< 8mm the rules for nails and with




8mm the
rules for bolts apply

-
Reduction of load bearing capacity for many fasteners in a row with
exception of nails


Design of Timber Structures

EC 5
-
1
-
1

Connections

Start values

General:

-
Take into account minimum edge and space distances of fasteners

-
If the force direction deviates from the grain direction, tension perp. to
grain has to be taken into account

-
The slip modulus of a connection for the ultimate limit state, K
u

,skould
be taken as:

K
u

= 2/3 *K
ser

Design of Timber Structures

EC 5
-
1
-
1

Connections

Parallel acting of different fasteners


Different slip moduli!!!

No parallel acting of glue and fasteners!

Design of Timber Structures

EC 5
-
1
-
1

Connections

Reduction of load bearing capacity


If alternate medium and long term actions occur (tension F
t

and
compression F
c
) the calculation should be done by

F
t,d

+ 0,5*F
c,d

F
c,d

+ 0,5*F
t,d


Design of Timber Structures

EC 5
-
1
-
1

Connections

Weakening of cross section


Reduction of cross section has to be taken into account.


Exceptions

-
Non
-
predrilled nails up to 6 mm diameter

-
Holes in the compression area, if they are filled with a material with a MOE
equal or higher of the timber

-
Cross section reduction shall be taken into account in an area of

mina/2

a=minimumspacingo映晡s瑥nes


Design of Timber Structures

EC 5
-
1
-
1

Connections

Lateral load carrying capacity


Different rules for:

-
Fasteners in single
-

and double
-
shear in timber
-
to
-
timber and timber
-
to
-
panel connections

-
Fasteners in single
-

and double
-
shear in timber
-
to
-
steel connections
with thin and thick steel plates (thin: t


0,5 d)

-
Multiple shear plane connections


Design of Timber Structures

EC 5
-
1
-
1

Connections

Thin and thick steel plates


Single shear plane timber
-
steel
-
connection


Thin steel plate

F



Twisting dowel

Thick steel
plate

F




Partly cantilevered


dowel;




In捲ca獥loa
-


bea物ng捡pa捩y

Design of Timber Structures

EC 5
-
1
-
1

Connections

Validity


Rules apply for nails, staples, bolts, dowels and screws




The characteristic value F
v,Rk

applies
per

fastener and
per

shear plane

Design of Timber Structures

EC 5
-
1
-
1

Connections

timber
-

timber/panel
-
connections


Start values:

t1 , t2

Thickness of timber/panel or penetration depth

f
h,i,k

,

Characteristic embedment strength



f
h,1,
/ f
h,2,k

d

Fastener diameter

M
y,k

Characteristic fastener yield moment

Design of Timber Structures

EC 5
-
1
-
1

Connections


Single shear plane



calculation of F
v,k





Embedment

strength failure

timber
-

timber/panel
-
connections

Design of Timber Structures

EC 5
-
1
-
1

Connections


Single shear plane


calculation of F
v,k


Fastener yield moment and embedment strength failure

timber
-

timber/panel
-
connections

Design of Timber Structures

EC 5
-
1
-
1

Connections

timber
-

timber/panel
-
connections


Calculation of design value:

with

M

= 1,3 for connections and


if two different materials are
involved (see clause 2.3.2.1)


Design of Timber Structures

EC 5
-
1
-
1

Connections

Multiple shear plane connections

t
a

t

t
i

t

t
a

A

B

A

bolt

Steel plate

B

1

2

3

4

4 shear planes

Design of Timber Structures

EC 5
-
1
-
1

Connections

Multiple shear plane connections

A

B

A

B

1)

Shear plane(s)
A

2)

Shear plane(s)
B

t
a

t

t
i

t

t
a

A

B

A

B

Design of Timber Structures

EC 5
-
1
-
1

Connections

exterior shear plane

1)

Shear plane(s)
A

calculation as a double shear
plane connection with inner
steel plate

Design of Timber Structures

EC 5
-
1
-
1

Connections

Interior shear plane

calculation as double shear
plane connection with exterior
steel plate

2) shear plane(s)
B


thick steel plates

Design of Timber Structures

EC 5
-
1
-
1

Connections

Interior shear plane




The exterior timber creates the same effect
as a thick steel plate, independent from the real
thickness of the plate

F

F

Thin steel
plate

EC 5
-
1
-
1

Design of Timber Structures

Joints

Examples for bolt resp. dowel joints:



EC 5
-
1
-
1

Design of Timber Structures

Joints

Dowel
-
type fasteners:

Load
-
carrying capacity R
d

for connections with solid timber C 24
with steel dowels S 235, per shear plane

Service class 2, medium term action

Design of Timber Structures

EC 5
-
1
-
1

Connections

Nail plates / other connectors

Nail plate

System Greim
(thin steel plates


nail connection

Multi
-
dowel (nail) clamp

EC 5
-
1
-
1

Design of Timber Structures

Joints

d
c
h
e
h
e
d
c
h
e
h
e
d
c
h
e
h
e
h
e
d
c
h
e
Connectors

Split ring and tooth plate connectors

Type A1, B1



C1, C2,



C 19, C 11

EC 5
-
1
-
1

Design of Timber Structures

Joints

t

t

Split ring and tooth plate connectors

Type A1, B1



C1, C2,



C 19, C 11

EC 5
-
1
-
1

Design of Timber Structures

Joints

Split ring and tooth plate connectors

Diameter d
c

in mm

Design resistance per shear plane


Service class 2, medium term action

Design of Timber Structures

EC 5
-
1
-
1

Connections

Screws and staples

staple

EC 5
-
1
-
1

Design of Timber Structures

Joints

Connections with screws

According to EC 5 or DIN


Screws with type Approval

Without Predrilling


www.spax.com

www.sfsintec.biz




EC 5
-
1
-
1

Design of Timber Structures

Joints

Subjected to shear

0,5∙F

0,5∙F

F

EC 5
-
1
-
1

Design of Timber Structures

Joints

Subjected to shear

Strong rope effect higher design resistance



EC 5
-
1
-
1

Design of Timber Structures

Joints


Fixing system WT of SFSintec:

EC 5
-
1
-
1

Design of Timber Structures

Joints

EC 5
-
1
-
1

Design of Timber Structures

Joints

Fixing system WT of SFSintec:

Examples for use:

EC 5
-
1
-
1

Design of Timber Structures

Joints

Fixing system WT of SFSintec: